about processes and engines

Archive for the ‘scheduling’ Category

taskr – restful scheduler – by Matt Zukowski

Matt just announced he developed Taskr a RESTful cron / scheduler daemon written in Ruby.

A cron / scheduler managed via REST, that’s neat. PUT a task for execution in 5 days or every day at 6 am. There are facilities for the tasks to interact with other RESTful services.


It’s based on Camping and on the OpenWFEru scheduler. For the Ruby on Rails aficionados, there is a Taskr Rails plugin.

I like the idea, it’s very focused, with a big potential. Congrats to Matt !

Written by John Mettraux

January 4, 2008 at 4:09 pm

rails and periodic tasks

I came across this post by Joseph Pearson : “Scheduling periodic tasks in a Rails application”, it features a nice combination of the OpenWFEru scheduler with the Daemons gem. Joseph’s company, Inventive Labs, is using it into its BluePrint CMS.

The introducing remark on OpenWFEru made me laugh :

OpenWFEru is a Workflow Engine, which sounds impressively enterprisey. I don’t know much about that, but it comes with a pretty good scheduler

True enough, “workflow” and “bpm” do sound ‘enterprisey’. That started me into a thread of reflection, somehow, I’m really hoping to make workflow (business process) management less enterprisey by providing OpenWFEru (Rufus). Business processes can be found in each of the application we, developers, create (modify) every day, a BPMS solution simply tries hard to make them “1st class” citizens, readily available for examination and manipulation (management).

This scheduler is used by more and more people, that’s great.

Written by John Mettraux

November 21, 2007 at 1:28 pm

cron schedule, to the second

The venerable cron unix utility allows for schedule up to the minute.

The OpenWFEru scheduler schedule method mimicks it for the Ruby platform, so until now, it went up to the minute as well. I felt it was sufficient, but of course, someone asked for schedules up to the second.

So here we go :

require 'rubygems'
require 'openwfe/util/scheduler'

scheduler =

scheduler.schedule "7,27,30 * * * * 1-5" do

    puts "the second is now 7, 27 or 30"
    puts "and it's not Sunday or Caturday..."

The OpenWFEru scheduler is available as a gem from the OpenWFEru download page, or via the usual sudo gem install openwferu-scheduler.

The OpenWFEru scheduler documentation is available as well.

(seems like Syntax Highlighted content input works better from Safari, Firefox seemed to get in the way… Weird…)

Written by John Mettraux

October 18, 2007 at 11:37 pm

Posted in ruby, scheduling

tags for scheduled jobs

TagHeuer watchIt’s a feature requested by Lee Fyock : be able to tag jobs at schedule time.

The OpenWFEru scheduler is a tiny Ruby library for scheduling jobs à la “at” or à la “cron”. It’s part of OpenWFEru, but it’s also available in its own gem ‘openwferu-scheduler’.

Here are some examples of the scheduler, with and without tags :

scheduler examples

A schedule now accepts a :tags attribute with one or more “tags”. It’s easy then to ask the scheduler for jobs that bear a certain tag.

Enjoy ! Feedback is welcome.

Written by John Mettraux

October 7, 2007 at 6:10 am

Posted in openwferu, ruby, scheduling

launch at

Pat suggested the extension of the launch method of the OpenWFEru engine as follow :


Why not ? It’s already possible to do that by launching a simple process wrapping the call to the main process inside a ‘cron’ or or after a ‘sleep’, but why not a bit of abstraction ?

It should be available in OpenWFEru 0.9.14.

On another front, the ‘densha‘ web application is getting better every day. Thanks to Juan-Pedro for his feedback and patches !

Written by John Mettraux

September 9, 2007 at 2:13 pm

gem install openwferu-scheduler

update (2008/02) : the openwferu-scheduler gem has changed its name to rufus-scheduler.

jlc.jpgThe OpenWFEru scheduler is a small library for scheduling tasks in Ruby.

It’s used within the OpenWFEru workflow and bpm engine for expressions like ‘when’, ‘cron’, ‘sleep’, ‘wait’…

As it makes sense also outside of OpenWFEru, I packaged it in its own gem.

You can now do “[sudo] gem install openwferu-scheduler” to get a simple scheduler but not the whole OpenWFEru bpm circus.

Written by John Mettraux

April 3, 2007 at 1:49 am

ruby task scheduling

Ilya Grigorik wrote a nice blog post about scheduling for Ruby. He presents three solutions with a code example for each of them.

Among the solution he details, there is our OpenWFEru scheduler.

The project BackgrounDRB seems very interesting as well.

Ilya’s previous post was great : an RSS aggregator in 26 lines of Ruby code.

Written by John Mettraux

March 29, 2007 at 2:30 pm

Posted in openwferu, ruby, scheduling